Mechanism And Simulation Of CO₂ Decalcification In Ca²⁺、Mg²⁺//Cl^--H₂O System

CO₂ decalcification technology is a new pretreatment method of decalcification.This technology promotes a method to remove calcium ions in seawater by the CO₂ in the flue gas.However,the research of this technology is still in the preliminary stage,there are few reports on the mechanistic studies and there is a lack of mature theoretical guidance.This topic is based on the previous study.Firstly,this research promotes a series of experiments with Mg（OH）₂ and MgO as alkali source in Ca²⁺、Mg²⁺//Cl^--H₂O system,at the flow rate of CO₂ is 100mL/min,the temperature is 80℃.The changes of Ca²⁺,Mg²⁺and alkalinity with the time of reaction were obtained.Combined with the characterization of the sediments,it was confirmed that the reaction of activated MgO with CO₂ has the highest reactivity.It can react fastest to reach equilibrium,and it is presents the best decalcification efficiency.Secondly,combining thermodynamic calculations in this system,it is confirmed that the main reactions are MgO and Mg（OH）₂ directly reacting with solvated CO₂,and the pyrolysis of HCO₃^-.Thirdly,the experiment system was studied and the mass transfer kinetics of bubble reaction was modelling.Bubble distribution in the reaction was determined.On the basis of mechanism in this study,a kinetics chemical reactiton simulation model was established,and the kinetic Monte-Carlo algorithm was used to perform dynamic simulation.With the verification,the simulation results are basically consistent with the experimental results.